Understanding the output of "git show-branch"

git show-branch is a tool that I use infrequently enough that every time I do so I end up having to look up the output format in the man page. This is a weakness I've developed while leaning on the crutch that is gitk --all.

But the output of git show-branch is really not that opaque and a simple-enough example should suffice:

What do the lines above the -- mean?

* [master] msg: is saying, the currently checked out HEAD (indicated by the *) corresponds to the master branch, and msg is the latest commit on the branch

! [maint] msg: is saying, a non-HEAD branch (indicated by the !) is the maint branch, and msgis the latest commit on that branch

What do the lines below the -- mean? =

all the lines labelled with a * are commits on the HEAD branch (in this case, master); in this case note how they all line up in column two, which was the column where the * appeared in the "table header" area

all of the lines labelled with + are commits on another branch (in this case, maint); note how they all line up in column one, which was the column where the maint branch's ! appeared in the "table header" area

any lines labelled with - (none in the example diagram) are merge commits

So in the example we have one commit which is only on the master branch, and another which is in both maint and master.